/******************************************************************************
 * Copyright 2018 The Apollo Authors. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *****************************************************************************/
#pragma once

#include <iostream>
#include <map>
#include <vector>

namespace apollo {
namespace perception {
namespace base {

class Polynomial {
 public:
  Polynomial();
  ~Polynomial();
  double& operator[](const uint32_t& order);
  // sum(coeff_[i] * x^i)
  double operator()(const double& x);

  const std::map<uint32_t, double>& getCoeff() const;

 private:
  std::map<uint32_t, double> coeff_;
  std::vector<uint32_t> index_gap_;
  std::map<uint32_t, double> power_cache_;
  bool initialized_ = false;
};

std::ostream& operator<<(std::ostream& o, const Polynomial& p);

}  // namespace base
}  // namespace perception
}  // namespace apollo
